Filter circuit

Abstract

There is provided a filter circuit provided in a plasma processing device for processing a substrate using plasma generated using power of a first frequency of 4 MHz or more and power of a second frequency of 100 Hz or more and less than 4 MHz. The filter circuit comprises: a first filter provided in a wiring between a conductive member provided in the plasma processing device and a power supply configured to supply power of a third frequency of less than 100 Hz or control power which is direct-current (DC) power, to the conductive member; and a second filter provided in a wiring between the first filter and the power supply.

The invention claimed is: 
     
       1. A filter circuit provided in a plasma processing device for processing a substrate using plasma generated using power of a first frequency of 4 MHz or more and power of a second frequency of 100 Hz or more and less than 4 MHz, the filter circuit comprising:
 a first filter provided in a wiring between a conductive member provided in the plasma processing device and a power supply configured to supply power of a third frequency of less than 100 Hz or control power which is direct-current (DC) power, to the conductive member; and 
 a second filter provided in a wiring between the first filter and the power supply, 
 wherein the first filter includes: 
 a first coil which is connected to the wiring in series and which has no core material or has a first core material with a relative permeability of less than 10; and 
 a series resonant circuit which is connected between the wiring and a ground and which has a coil and a capacitor which are connected in series, and 
 wherein the second filter includes a second coil which is connected to the wiring provided between the first coil and the power supply in series and which has a second core material with a relative permeability of 10 or more. 
 
     
     
       2. The filter circuit of  claim 1 , wherein the capacitor included in the series resonant circuit is a vacuum capacitor. 
     
     
       3. The filter circuit of  claim 1 , wherein the second core material includes a dust material, a permalloy, or a cobalt-based amorphous material. 
     
     
       4. The filter circuit of  claim 1 , wherein the second filter includes a capacitor provided between the ground and the wiring between the second coil and the power supply. 
     
     
       5. The filter circuit of  claim 1 , wherein the conductive member includes a heater configured to control a temperature of the substrate. 
     
     
       6. The filter circuit of  claim 1 , wherein a stray capacitance of each of a wiring between the conductive member and the first filter, a wiring between the first filter and the second filter, and a wiring between the second filter and the power supply is less than or equal to 500 pF. 
     
     
       7. The filter circuit of  claim 1 , wherein:
 the conductive member is provided as a plurality of conductive members in the plasma processing device; 
 the first filter includes a plurality of first coils identical to the first coil and one or more series resonant circuits identical to the series resonant circuit; 
 the first coils are respectively provided with respect to the conductive members; and 
 one of the series resonant circuits is provided in common with respect to two or more of the first coils. 
 
     
     
       8. The filter circuit of  claim 1 , wherein:
 the conductive member is provided as a plurality of conductive members in the plasma processing device; 
 the first filter includes a plurality of first coils which are identical to the first coil and which are respectively provided with respect to the conductive members; 
 the series resonant circuit includes a plurality of coils, which are respectively provided with respect to the conductive members, and one or more capacitors; 
 the coils included in the series resonant circuit are respectively connected to the first coils in series; and 
 one capacitor included in the series resonant circuit is provided in common with respect to one or more of the first coils and one or more of the coils included in the series resonant circuit. 
 
     
     
       9. The filter circuit of  claim 1 , wherein the power of the first frequency includes power of a plurality of different frequencies, and the series resonant circuit includes a plurality of individual series resonant circuits, each having a frequency of each power as each resonant frequency. 
     
     
       10. A filter circuit provided in a plasma processing device for processing a substrate using plasma generated using power of a first frequency of 4 MHz or more and power of a second frequency of 100 Hz or more and less than 4 MHz, the filter circuit comprising:
 a first filter provided in a wiring between a plurality of conductive members provided in the plasma processing device and a power supply configured to independently supply power of a third frequency of less than 100 Hz or control power which is direct-current (DC) power, to each of the conductive members; and 
 a second filter provided in a wiring between the first filter and the power supply, 
 wherein the first filter includes: 
 a plurality of first coils which are respectively provided with respect to the conductive members, each of which is connected in series to the wiring connected to each conductive member and each of which has no core material or a first core material with a relative permeability of less than 10; and 
 one or more capacitors connected between a ground and the wiring between the first coil and the second filter, wherein one of the one or more capacitors is provided in common with respect to two or more of the first coils, and wherein the second filter includes a plurality of second coils which are respectively provided with respect to the conductive members, which are respectively connected in series to the wiring provided between the first coil and the power supply, and each of which has a second core material with a relative permeability of 10 or more.